Power supply systems are pervasive in many electronic applications from computers to automobiles. Generally, voltages within a power supply system are generated by performing a DC-DC, DC-AC, and/or AC-DC conversion by operating a switch loaded with an inductor or transformer. One class of such systems includes switch-mode power supply (SMPS). An SMPS is usually more efficient than other types of power conversion systems because power conversion is performed by controlled charging and discharging of the inductor or transformer and reduces energy lost due to power dissipation caused by resistive voltage drops.
Specific topologies for SMPS comprise buck-boost converters and flyback converters, among others. A buck-boost converter typically makes use of an inductor whereas a flyback converter isolates a load and may multiply the voltage conversion ratio through the use of a transformer. In addition to the energy storage element (either inductor or transformer), the operation of the switch is of particular importance, especially in high voltage applications.
A power supply can be designed to regulate current instead of voltage. Current controlled power supply systems may be used in electronic applications that are particularly susceptible to current and current variations, such as those related to light emitting diodes, (LEDs).